Method and apparatus for generating a desired three-dimensional digital model of an orthodontic structure

ABSTRACT

A method and apparatus for generating a three-dimensional digital model of a desired orthodontic structure include processing that begins by obtaining a three-dimensional model of an actual orthodontic structure, wherein the three-dimensional digital model is defined in x, y, z space. The processing then continues by generating an interim three-dimensional model of the desired orthodontic structure less teeth. The interim three-dimensional model is designed in x, y, z space and includes the desired placement of an occlusal plane, an upper-arch form, a lower-arch form, an upper-arch midline, and a lower- arch midline. The processing then continues by positioning the upper and lower teeth with respect to the interim digital model and the defined x, y, z space to obtain a first pass three-dimensional digital model of the desired orthodontic structure. The processing continues by determining whether achieving the first pass three-dimensional model is feasible. When achieving the first pass three-dimensional image is feasible, the processing continues by utilizing the first pass three-dimensional model as the desired three-dimensional digital model.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to the practice of orthodontics and inparticular to a method and apparatus for treating an orthodonticpatient.

BACKGROUND OF THE INVENTION

Orthodontic is known to be the practice of manipulating a patient'steeth to provide better function and appearance. In general, bracketsare bonded to a patient's teeth and coupled together with an archedwire. The combination of the brackets and wire provide a force on theteeth causing them to move. Once the teeth have moved to a desiredlocation and are held in a place for a certain period of time, the bodyadapts bone and tissue to maintain the teeth in the desired location. Tofurther assist in retaining the teeth in the desired location, a patientmay be fitted with a retainer.

To achieve tooth movement, orthodontists utilize their expertise tofirst determine a three-dimensional mental image of the patient'sphysical orthodontic structure and a three-dimensional mental image of adesired physical orthodontic structure for the patient, which may beassisted through the use of x-rays and/or models. Based on these mentalimages, the orthodontist further relies on his/her expertise to placethe brackets and/or bands on the teeth and to manually bend (i.e.,shape) wire, such that a force is asserted on the teeth to repositionthe teeth into the desired physical orthodontic structure. As the teethmove towards the desired location, the orthodontist makes continualjudgments as to the progress of the treatment, the next step in thetreatment (e.g., new bend in the wire, reposition or replace brackets,is head gear required, etc.), and the success of the previous step.

In general, the orthodontist makes manual adjustments to the wire and/orreplaces or repositions brackets based on his or her expert opinion.Unfortunately, in the oral environment, it is impossible for a humanbeing to accurately develop a visual three-dimensional image of anorthodontic structure due to the limitations of human sight and thephysical structure of a human mouth. In addition, it is humanlyimpossible to accurately estimate three-dimensional wire bends (with anaccuracy within a few degrees) and to manually apply such bends to awire. Further, it is humanly impossible to determine an ideal bracketlocation to achieve the desired orthodontic structure based on themental images. It is also extremely difficult to manually place bracketsin what is estimated to be the ideal location. Accordingly, orthodontictreatment is an iterative process requiring multiple wire changes, withthe process success and speed being very much dependent on theorthodontist's motor skills and diagnostic expertise. As a result ofmultiple wire changes, patient discomfort is increased as well as thecost. As one would expect, the quality of care varies greatly fromorthodontist to orthodontist as does the time to treat a patient.

As described, the practice of orthodontic is very much an art, relyingon the expert opinions and judgments of the orthodontist. In an effortto shift the practice of orthodontic from an art to a science, manyinnovations have been developed. For example, U.S. Pat. No. 5,518,397issued to Andreiko, et. al. provides a method of forming an orthodonticbrace. Such a method includes obtaining a model of the teeth of apatient's mouth and a prescription of desired positioning of such teeth.The contour of the teeth of the patient's mouth is determined, from themodel. Calculations of the contour and the desired positioning of thepatient's teeth are then made to determine the geometry (e.g., groovesor slots) to be provided. Custom brackets including a special geometryare then created for receiving an arch wire to form an orthodontic bracesystem. Such geometry is intended to provide for the disposition of thearched wire on the bracket in a progressive curvature in a horizontalplane and a substantially linear configuration in a vertical plane. Thegeometry of the brackets is altered, (e.g., by cutting grooves into thebrackets at individual positions and angles and with particular depth)in accordance with such calculations of the bracket geometry. In such asystem, the brackets are customized to provide three-dimensionalmovement of the teeth, once the wire, which has a two dimensional shape(i.e., linear shape in the vertical plane and curvature in thehorizontal plane), is applied to the brackets.

Other innovations relating to bracket and bracket placements have alsobeen patented. For example, such patent innovations are disclosed inU.S. Pat. No. 5,618,716 entitled “Orthodontic Bracket and Ligature” amethod of ligating arch wires to brackets, U.S. Pat. No. 5,011,405“Entitled Method for Determining Orthodontic Bracket Placement,” U.S.Pat. No. 5,395,238 entitled “Method of Forming Orthodontic Brace,” andU.S. Pat. No. 5,533,895 entitled “Orthodontic Appliance and GroupStandardize Brackets therefore and methods of making, assembling andusing appliance to straighten teeth”.

Unfortunately, the current innovations to change the practice oforthodontic from an art to a science have only made limited progress.This limit is due to, but not restricted to, the brackets being thefocal point for orthodontic manipulation. By having the brackets as thefocal point, placement of each bracket on a corresponding tooth iscritical. Since each bracket includes a custom sized and positioned wireretaining groove, a misplacement of a bracket by a small amount (e.g.,an error vector having a magnitude of millimeter or less and an angle ofa few degrees or less) can cause a different force system (i.e.,magnitude of movement and direction of movement) than the desired forcesystem to be applied to the tooth. As such, the tooth will not berepositioned to the desired location.

Another issue with the brackets being the focal point is that once thebrackets are placed on the teeth, they are generally fixed for theentire treatment. As such, if the treatment is not progressing asoriginally calculated, the orthodontist uses his or her expertise tomake the appropriate changes. The treatment may not progress asoriginally calculated for several reasons. For example, misplacement ofa bracket, misapplication of a bend in the wire, loss or attrition of abracket, bonding failure, the patient falls outside of the “normal”patient model (e.g., poor growth, anatomical constraints, etc.), patientlack of cooperation in use of auxiliary appliance, etc. are factors indelayed treatment results. When one of these conditions arise, theorthodontist utilizes his or her expertise to apply manual bends to thewire to “correct” the errors in treatment. Thus, after the originalscientific design of the brackets, the practice of the orthodonticconverts back to an art for many patients for the remainder of thetreatment.

Another issue with the brackets being the focal point is that customizedbrackets are expensive. A customized bracket is produced by milling apiece of metal (e.g., stainless steel, aluminum, ceramic, titanium,etc.) and tumble polishing the milled bracket. While the milling processis very accurate, some of the accuracy is lost by tumble polishing.Further accuracy is lost in that the placement of the brackets on theteeth and installation of the wire are imprecise operations. As isknown, a slight misplacement of one bracket changes the force onmultiple teeth and hinders treatment. To assist in the placement of thecustom brackets, they are usually shipped to the orthodontist in aninstallation jig. Such an installation jig is also expensive. Thus, suchscientific orthodontic treatment is expensive and has many inherentinaccuracies.

Therefore, a need exists for a method and apparatus that generates athree-dimensional digital model of an orthodontic structure such that ascientific approach to orthodontics is realized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic block diagram of an orthodontic servicesystem in accordance with the present invention;

FIGS. 2A-2E illustrate front, right side, left side, lower arch andupper arch views, respectively, of a graphical representation of athree-dimensional digital model of an actual orthodontic structure inaccordance with the present invention;

FIGS. 3A-3E illustrate front, right side, left side, lower arch andupper arch views, respectively, of a graphical representation of aninterim three-dimensional model of a desired orthodontic structure inaccordance with the present invention;

FIGS. 4A-4E illustrate front, right side, left side, lower arch andupper arch views, respectively, of a graphical diagram of athree-dimensional digital model of a desired orthodontic structure inaccordance with the present invention;

FIG. 5 illustrates a logic diagram of a method for generating athree-dimensional digital model of a desired orthodontic structure inaccordance with the present invention; and

FIGS. 6 and 7 illustrate a logic diagram of the method steps 60 through68 of FIG. 5.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Generally, the present invention provides a method and apparatus forgenerating a three-dimensional digital model of a desired orthodonticstructure. Such a method and apparatus include processing that begins byobtaining a three-dimensional model of an actual orthodontic structure,wherein the three-dimensional digital model is defined in x, y,z space.The processing then continues by generating an interim three-dimensionalmodel of the desired orthodontic structure less teeth. The interimthree-dimensional model is designed in x, y, z space and includes thedesired placement of an occlusal plane, an upper-arch form, a lower-archform, an upper-arch midline, and a lower-arch midline. The processingthen continues by positioning the upper and lower teeth with respect tothe interim digital model and the defined x, y, z space to obtain afirst pass three-dimensional digital model of the desired orthodonticstructure. The processing continues by determining whether achieving thefirst pass three-dimensional model is feasible. In essence, thedetermination is based on treatment constraints and whether the desiredorthodontic structure can be achieved from the actual orthodonticstructure given such constraints. When achieving the first passthree-dimensional image is feasible, the processing continues byutilizing the first pass three-dimensional model as the desiredthree-dimensional digital model. With such a method and apparatus,automation of orthodontic treatment is realized thereby providing ascientific approach to practice of orthodontics.

The present invention can be more fully described with reference toFIGS. 1 through 7. FIG. 1 illustrates a schematic block diagram of anorthodontic servicing system 10 that includes a site orthodontic system12, an orthodontic server 14, a communication network 16, and a databaseof orthodontic parameters 24. In operation, the site orthodontic system12 scans 26 the patient's 18 orthodontic structure (i.e., teeth, gums,lips, upper and lower arches, and/or other facial features). The siteorthodontic system 12 converts the scanned images of the orthodonticstructure of the patient to produce a digital model of the actualorthodontic structure 28. The orthodontic server 14 receives the digitalmodel of the actual orthodontic structure 28 via the communicationnetwork 16. The communication network 16 may be a direct connect, theInternet, local area network, wide area network, and/or any device thatenables the transference of digital information from one computing typesystem to another.

The orthodontic server 14 includes a processing module 20 and memory 22.The processing module 20 may be a single processing device or aplurality of processing devices. Such a processing device may be amicroprocessor, microcomputer, microcontroller, digital signalprocessor, central processing unit, state machine, logic circuitry,and/or any device that manipulates signals (e.g., analog and/or digital)based on operational instructions. The memory 22 may be a single memorydevice or a plurality of memory devices. Such a memory device may be aread-only memory, random access memory, floppy disk memory, hard drivememory, system memory, flash memory and/or any device that storesdigital information. Note that when the processing module 20 implementsone or more of its functions via a state machine or logic circuitry, thememory storing the corresponding operational instructions is embeddedwithin the circuitry comprising the state machine or logic circuitry.

The orthodontic server 14 generates a three-dimensional digital model ofthe desired orthodontic structure 30 from the digital model of theactual orthodontic structure 28 and orthodontic parameters contained inthe database of orthodontic parameters 24. To achieve this, theprocessing module 20, via operational instructions stored in memory 22,performs the processing steps of FIGS. 5 through 7, which will bediscussed below. For a more detailed discussion for the site orthodonticsystem 12, the orthodontic server 14, and the database of orthodonticparameters 24 refer to co-pending patent application having Ser. No.09/451,637 and entitled METHOD AND APPARATUS FOR DETERMINING ANDMONITORING ORTHODONTIC TREATMENT, co-pending patent application having aSer. No. 09/451,560 and entitled METHOD AND APPARATUS FOR TREATING ANORTHODONTIC PATIENT, and co-pending patent application having Ser. No.09/452,038 and entitled METHOD AND APPARATUS FOR SITE TREATMENT OF ANORTHODONTIC PATIENT, each having a filing date the same as the presentpatent application and is assigned to the same assignee as the presentpatent application.

FIG. 2 illustrates a graphical representation of the three-dimensionaldigital model of an actual orthodontic structure 28. As shown, theorthodontic structure is mapped to x, y, z space. For a detaileddiscussion of the mapping of the digital model to x, y, z space refer toco-pending patent application having Ser. No. 09/452,034 and entitledMETHOD AND APPARATUS FOR PRODUCING A THREE-DIMENSIONAL DIGITAL MODEL OFAN ORTHODONTIC PATIENT, which has a filing date the same as the presentpatent application and is assigned to the same assignee as the presentpatent application. As shown, the three-dimensional digital model of theactual orthodontic structure 28 includes surface images for the teeth 32and gums 34. The three-dimensional model may further include surfaceimages of the bone structure, lips, and other soft facial tissues. Thegeneration of the three-dimensional digital model of the actualorthodontic structure 28 is further described in the previouslymentioned co-pending patent application having Ser. No. 09/452,034.

FIG. 3 illustrates a graphical diagram of an interim three-dimensionaldigital model of the desired orthodontic structure 40. In thisillustration, the teeth have been removed from the upper and lower gums.In addition, the upper arch and lower arch have been positioned inaccordance with an occlusal plane 42. As is known, the occlusal plane 42defines a plane between the upper arch and the lower arch where, in anideal orthodontic structure, the upper and lower teeth meet. In additionto aligning the upper and lower arches to the occlusal plane, the upperarch is aligned in accordance with the upper arch midline 44. The lowerarch is further aligned in accordance with the lower-arch midline 46. Ina desired orthodontic structure, the upper-arch midline 44 is coincidentwith the lower-arch midline 46. In addition to positioning the upper andlowery arches in accordance with the occlusal plane 42 the upper-archmidline 44 and the lower-arch midline 46, the shapes of the upper andlower arches may also be redefined. For example, the upper arch may bereshaped to provide a more ideal arch shape. Similarly, the lower archmay be reshaped to provide a more ideal arch shape. As a furtherexample, the lower arch may be reshaped to better match the upper-arch,or vice-versa. Such modification of the arches, and other aspects of theinterim three-dimensional digital model of the desired orthodonticstructure 40, is done in the digital domain to enable an orthodonticpractitioner to “experiment” with different treatment options.Accordingly, the practitioner may digitally modify the patient'sorthodontic structure to obtain a desired appearance and/or functionprior to applying any orthodontic apparatus on the patient.

FIG. 4 illustrates a graphical representation of the three-dimensionalmodel of the desired orthodontic structure 30. In this illustration, theteeth have been positioned in the interim three-dimensional digitalmodel of the desired orthodontic structure 40 to be in desiredpositioning. Accordingly, the upper teeth and lower teeth meet at theocclusal plane 42. In addition, the upper and lower arches arepositioned such that the interaction of the upper teeth and lower teethis functionally appropriate. As shown, in the right and left sides ofthe desired orthodontic structure 30, the lower molars are offset byapproximately half of the distance of the upper molars, such that thefunction of the teeth is proper. In addition, the lower arch is slightlysmaller than the upper-arch such that the upper and lower teeth alignwith the appropriate function. Note that the positioning of the teeth inthe desired orthodontic structure 30 may be done in an automatedprocess, i.e., calculated based on parameters provided to theorthodontic server 14. Alternatively, the teeth may be positioned in aninteractive approach wherein a practitioner provides input as to theplacement of the teeth. In the interactive approach, the orthodonticserver 14 records the inputs and positions the teeth accordingly.

FIG. 5 illustrates a logic diagram of a method for generating athree-dimensional digital model of a desired orthodontic structure. Theprocess begins at step 50 where a three-dimensional digital model of anactual orthodontic structure is obtained. The three-dimensional digitalmodel of the actual orthodontic structure is defined in x, y, z space.The process then proceeds to step 52 where a determination is made as towhether growth of the orthodontic structure will occur during treatmentor whether a new tooth will erupt. If so, the process proceeds to step54 where growth parameters and/or tooth parameters are obtained fromdatabase 28.

Whether growth will occur or not, the process proceeds to step 56. Atstep 56 an interim three-dimensional digital model of the desiredorthodontic structure is generated without teeth. The interimthree-dimensional model includes desired placement of the occlusalplane, the upper-arch form, the lower-arch form, an upper-arch midlineand/or the lower-arch midline. The process then proceeds to step 58where the upper and lower teeth are positioned with respect to theinterim three-dimensional digital model to obtain a first passthree-dimensional digital model of the desired orthodontic structure.Note that if growth will occur during the treatment, the interimthree-dimensional digital model is modified to include the growthaspects. For example, if it is determined during the course oftreatment, the orthodontic structure will grow by two percent, the twopercent is factored into the interim three-dimensional digital model. Inaddition, the process may use a primary factor in positioning the upperand lower teeth. The primary factor relates to the desired orthodonticstructure and may be soft tissue appearance, dental appearance, dentaland/or oral function, stability, and/or hard tissue positioning. Assuch, if the primary factor is dental appearance, the teeth will bepositioned to provide the best appearance, with function and soft tissueappearance being secondary considerations. Of course, it is desirable toproduce the ideal orthodontic structure that does not compromise dentalappearance, soft tissue appearance, and dental function. In situationswhere the ideal orthodontic structure cannot be obtained, the primaryfactor is used to provide the patient with as close to the idealorthodontic structure as possible.

The positioning of the upper and lower teeth may be done in an automatedprocess, on a tooth by tooth basis, such that the orthodontic server 14automatically positions the teeth into a desired location in accordancewith the primary factor. Alternatively, the positioning of the upper andlower teeth may be done in an interactive approach. For example, anorthodontic practitioner may provide inputs as to the positioning ofeach of the upper and lower teeth. In this manner, the orthodonticpractitioner can place the teeth in the desired positions in accordancewith one or more of the primary factors. As such, each tooth is treatedas an independent entity for the purposes of ideal placement.

The process then proceeds to step 60 where a determination is made as towhether achieving the first pass three-dimensional digital model isfeasible (the determination of feasibility is discussed below withreference to FIGS. 6 and 7). If yes, the process proceeds to step 62where the first pass three-dimensional digital model is used as thedesired three-dimensional model. If, however, achieving the first passthree-dimensional digital model is not feasible, the process proceeds tostep 64. At step 64, a modification to the digital model or the interimthree-dimensional digital model is determined. Such a modificationinclude changing the position of a tooth, changing the occlusal plane,the upper and lower arch, the midline for the upper and/or lower arch,etc.

The process then proceeds to step 66 where a determination is made as towhether achieving the revised three-dimensional model is feasible. Ifnot, the process reverts to step 64 where another modification is madeto the digital model or the interim three-dimensional digital model.Once determining that the revised three-dimensional digital model isfeasible, the process proceeds to step 68. At step 68, the revisedthree-dimensional digital model is used as the desired three-dimensionaldigital model.

FIGS. 6 and 7 illustrate the operational instructions of steps 60through 68 in greater detail. The more detailed processing begins atstep 70 where a determination is made as to whether per tooth movementis feasible along a direct path and there is sufficient room in thearches to fit all of the teeth. The process for determining the pertooth movement is further described in co-pending patent applicationhaving Ser. No. 09/451,609, entitled METHOD AND APPARATUS FOR SIMULATINGTOOTH MOVEMENT FOR AN ORTHODONTIC PATIENT, now U.S. Pat. No. 6,250,918,having a filing date the same as the present patent application, and isassigned to the same assignee as the present patent application.

If the per tooth movement is feasible, the process proceeds to step 72where a determination is made as to whether all of the teeth are ofnormal size and form. If the teeth are of normal size and form, theprocess proceeds to step 74 where a determination is made as to whetherthe overall realignment of the teeth is feasible. Factors that affectthe overall realignment of the teeth include stability, aesthetics,function, occlusal scheme, cooperation of patient with use of extendedgear (e.g., head gear, rubber bands etc.), the physical aspects of thepatient including the physiological aspects, biological aspects, andanatomy. Further factors include the orientation of the roots, crownpositioning, intercuspation fit, treatment time, patient's expectations,and/or costs. If the overall realignment is feasible, the processing iscomplete and the desired three-dimensional digital model is obtained.

If the per tooth movement is not feasible, or the overall realignment ofthe teeth is not feasible, the process proceeds to step 86. At step 86,a determination is made as to whether additional treatment is required.If additional treatment is not required, the process proceeds to step 88where a determination is made as to whether at least one aspect of theinterim three-dimensional digital model requires changing. Accordingly,the determination at step 88 is determining whether the occlusal planeneeds to be changed, the shape of the upper or lower arch needs to bechanged, or the positioning of the upper or lower midline needs to bechanged. If so, the process proceeds to step 90 where at least oneaspect of the interim digital model is changed. Having done this, theprocess reverts to step 60 or 66 for further processing.

If, at step 88 it was determined that one aspect of the interimthree-dimensional digital model did not require changing, the processproceeds to step 91. At step 91, at least one tooth position is changedwithin the digital model of the desired orthodontic structure. At thispoint, the process reverts to step 60 or 66 for further processing. Notethat the determination of step 88 may be done in an automated mannerbased on case histories, patient information, desired results, etc.Alternatively, the determination at step 88 may be done in aninteractive process with an orthodontic practitioner. As such, theorthodontic practitioner may determine whether an aspect of the interimthree-dimensional digital model requires changing. In addition, theinteractive process may be utilized at step 91 to determine therepositioning of the tooth or teeth to obtain the desiredthree-dimensional model. Note that after step 90 or 91, the feasibilityof the revised digital model is tested prior to acceptance.

If, at step 72, it was determined that at least one tooth is not ofnormal size or form, the process proceeds to step 76. At step 76, adetermination is made as to whether the abnormal tooth will be used inthe three-dimensional digital model of the desired structure. If so, theprocess reverts to step 74. If, however, the abnormal tooth will not beused in the three-dimensional digital model, the process proceeds tostep 78. At step 78, a determination is made as to whether theabnormality relates to the tooth being too small. If so, the processproceeds to step 80 where the tooth is reshaped to be of normal sizebased on the corresponding opposite tooth or a normalized model. Havingdone this, the process reverts to step 60 or 66.

If the tooth is not abnormally small, the process proceeds to step 82where a determination is made as to whether the abnormality results froma missing tooth. If so, the process proceeds to step 84 where the toothis replaced in the digital model based on the corresponding oppositetooth or a normalized digital model. Having done this, the processproceeds to step 60 or 66. Note that step 76 through 84 may be done inan automated process by the orthodontic server or in an interactiveprocess between the orthodontic server 14 and an orthodonticpractitioner.

If it was determined that the abnormality was not due to a missingtooth, the process proceeds to step 102, which is shown on FIG. 7. Atstep 102, a determination is made as to whether the abnormal toothcorresponds to an extra tooth. If so, the extra tooth is removed at step104 from the digital model. Having removed the tooth, the processproceeds to step 66 or 60 of the logic diagram of FIG. 5.

If the abnormal tooth is not an extra tooth, the process proceeds tostep 106 where a determination is made as to whether the tooth istransposed. If the tooth is transposed, i.e., not in the appropriatespace, the process will proceed to step 104 where the tooth is removedfrom the digital model. If, however, the abnormal tooth is nottransposed, it may be a large tooth. The process then proceeds to step108 where the large tooth is reshaped to be of normal size based on thecorresponding opposite tooth or a normalized model for the tooth. Notethat the tooth may be abnormal due to a misalignment between the rootand crown, which is known as dilaceration. In this case, an interactiveprocess between the practitioner and the orthodontic server 14 would beconducted to position the tooth as best as possible.

If it was determined that additional treatment were required at step 86,of FIG. 6, the process would proceed to step 92, which is shown on FIG.7. At step 92, additional treatment options are determined. Suchadditional treatment options include extraction, oral surgery (e.g.,reshape the upper and/or lower arch) and/or cosmetic surgery (e.g.,change the lip structure, check bones, chin, etc.). The process proceedsto step 94 where a simulation for each of the additional treatmentoptions is conducted. Such simulation would occur in a sequential ordertesting one or more of the options. The process then proceeds to step 96where a determination is made as to whether at least one additionaltreatment option was acceptable. If so, the process reverts to step 60or 66 of FIG. 5. If not, the process proceeds to step 98 where acompromised three-dimensional digital model is utilized. Typically, if acompromised three-dimensional digital model will be utilized, theprocess will determine the least amount of compromise based on the idealorthodontic structure, the patient's requests, the primary factor, andbiological factors of the patient.

The preceding discussion has presented a method and apparatus forgenerating a three-dimensional digital model of a desired orthodonticstructure. By utilizing such a method and apparatus, in an orthodontictreatment system as shown in FIG. 1, the practice of orthodontictreatment may be corverted from an art to a science. As one of averageskill in the art will appreciate, other embodiments may be derived fromthe teaching of the present invention without deviating from the scopeof the claims.

What is claimed is:
 1. A method for generating a three-dimensionaldigital model of a desired orthodontic structure, the method comprisesthe steps of: a) obtaining a three-dimensional digital model of anactual orthodontic structure, wherein the three-dimensional digitalmodel is defined in x, y, z space; b) generating an interimthree-dimensional digital model of the desired orthodontic structureless teeth in the defined x, y, z space, wherein the interimthree-dimensional digital model includes desired placement of an upperand lower occlusal plane, an upper arch form, a lower arch form, anupper arch midline, and a lower arch midline; c) positioning upper andlower teeth with respect to the interim three-dimensional digital modelin the defined x, y, z space to obtain a first pass three-dimensionaldigital model of the desired orthodontic structure; d) determiningwhether achieving the first pass three-dimensional digital model isfeasible; and e) when achieving the first pass three-dimensional imageis feasible, utilizing the first pass three-dimensional digital model asthe desired three-dimensional digital model.
 2. The method of claim 1,wherein step (b) further comprises: determining whether growth willoccur during treatment based on patient parameters that are crossreferenced to a normalized patient; when growth will occur, obtaininggrowth parameters; and generating the interim three-dimensional digitalmodel based on the growth parameters.
 3. The method of claim 1, whereinstep (c) further comprises: determining a primary factor for desiredtooth placement within the desired orthodontic structure, wherein theprimary factor is at least one of: resulting soft tissue appearance,dental appearance, dental function, stability, and hard tissuepositioning.
 4. The method of claim 1, wherein step (d) furthercomprises: determining whether per tooth movement is feasible along adirect path for each tooth; when the per tooth movement is not feasible,determining whether additional treatment is required; when additionaltreatment is not required, determining whether at least one aspect ofthe interim three-dimensional digital model requires changing; and whenthe at least one aspect of the interim three-dimensional digital modeldoes not require changing, changing at least one tooth position withinthe first pass three-dimensional digital model.
 5. The method of claim 4further comprises: when the per tooth movement is feasible, determiningwhether all of the teeth are of normal size and form; when all of theteeth are of normal size and form, determining whether overallrealignment of the teeth is feasible; and when the overall realignmentof the teeth is feasible, determining that the first passthree-dimensional digital model is feasible.
 6. The method of claim 5further comprises: when at least one tooth is not of normal size orform, determining whether the at least one tooth will be used in thethree-dimensional digital model; and when the at least one tooth willnot be used in the three-dimensional digital model, determining a typeof abnormality.
 7. The method of claim 6, wherein the type ofabnormality is an abnormally small tooth, wherein the method furthercomprises reshaping the at least one tooth to be of normal size based onat least one of: a corresponding tooth on an opposite side of an archand a normalized model tooth.
 8. The method of claim 6, wherein the typeof abnormality is a missing tooth, wherein the method further comprisesreplacing the missing tooth based on at least one of: a correspondingtooth on an opposite side of an arch and a normalized model tooth. 9.The method of claim 6, wherein the type of abnormality is an extratooth, wherein the method further comprises removing the at least onetooth.
 10. The method of claim 6, wherein the type of abnormality is atransposed tooth, wherein the method further comprises extracting the atleast one tooth.
 11. The method of claim 6, wherein the type ofabnormality is an abnormally large tooth, wherein the method furthercomprises reducing the size of the at least one tooth based on acorresponding tooth on an opposite side of an arch and a normalizedmodel tooth.
 12. The method of claim 4 further comprises: when theadditional treatment is required, determining additional treatmentoptions; simulating, in a sequential manner, each of the additionaltreatment options; when at least one of the additional treatment optionsis acceptable, utilizing the at least one of the additional treatmentoptions.
 13. The method of claim 12 further comprises: when each of theadditional treatment options fails to provide an acceptable option,utilizing a compromised three-dimensional digital model.
 14. The methodof claim 4 further comprises: when the at least one aspect of theinterim three-dimensional digital model requires changing, changing theat least one aspect of the interim three-dimensional digital model. 15.An apparatus for generating a desired three-dimensional digital model ofan orthodontic structure, the apparatus comprises: a processing module;and memory operably coupled to the processing module, wherein the memoryincludes operational instructions that cause the processing module to:(a) obtain a three-dimensional digital model of an actual orthodonticstructure, wherein the three-dimensional digital model is defined in x,y, z space; (b) generate an interim three-dimensional digital model ofthe desired orthodontic structure less teeth in the defined x, y, zspace, wherein the interim three-dimensional digital model includesdesired placement of an occlusal plane, an upper arch form, a lower archform, an upper arch midline, and a lower arch midline; (c) positionupper and lower teeth with respect to the interim three-dimensionaldigital model in the defined x, y, z space to obtain a first passthree-dimensional digital model of the desired orthodontic structure;(d) determine whether achieving the first pass three-dimensional digitalmodel is feasible; and (e) when achieving the first passthree-dimensional image is feasible, utilize the first passthree-dimensional digital model as the desired three-dimensional digitalmodel.
 16. The apparatus of claim 15, wherein the memory furthercomprises operational instructions that cause the processing module to:determine whether growth will occur during treatment based on patientparameters that are cross referenced to a normalized patient; whengrowth will occur, obtain growth parameters; and generate the interimthree-dimensional digital model based on the growth parameters.
 17. Theapparatus of claim 15, wherein the memory further comprises operationalinstructions that cause the processing module to: determine a primaryfactor for desired tooth placement within the desired orthodonticstructure, wherein the primary factor is at least one of: resulting softtissue appearance, dental appearance, dental function, and hard tissuepositioning.
 18. The apparatus of claim 15, wherein the memory furthercomprises operational instructions that cause the processing module to:determine whether per tooth movement is feasible along a direct path foreach tooth; when the per tooth movement is not feasible, determinewhether additional treatment is required; when additional treatment isnot required, determine whether at least one aspect of the interimthree-dimensional digital model requires changing; and when the at leastone aspect of the interim three-dimensional digital model does notrequire changing, change at least one tooth position within the firstpass three-dimensional digital model.
 19. The apparatus of claim 18,wherein the memory further comprises operational instructions that causethe processing module to: when the per tooth movement is feasible,determine whether all of the teeth are of normal size and form; when allof the teeth are of normal size and form, determine whether overallrealignment of the teeth is feasible; and when the overall realignmentof the teeth is feasible, determine that the first passthree-dimensional digital model is feasible.
 20. The apparatus; of claim19, wherein the memory further comprises operational instructions thatcause the processing module to: when at least one tooth is not of normalsize or form, determine whether the at least one tooth will be used inthe three-dimensional digital model; and when the at least one toothwill not be used in the first-pass three-dimensional digital model,determine a type of abnormality.
 21. The apparatus of claim 20, whereinthe memory further comprises operational instructions that cause theprocessing module to, when the type of abnormality is an abnormallysmall tooth, reshape the at least one tooth in the first-passthree-dimensional digital model to be of normal size based on at leastone of: a corresponding tooth on an opposite side of an arch and anormalized model tooth.
 22. The apparatus of claim 20, wherein thememory further comprises operational instructions that cause theprocessing module to, when the type of abnormality is a missing tooth,replace the missing tooth in the first-pass three-dimensional digitalmodel based on at least one of: a corresponding tooth on an oppositeside of an arch and a normalized model tooth.
 23. The apparatus of claim20, wherein the memory further comprises operational instructions thatcause the processing module to, when the type of abnormality is an extratooth, remove the at least one tooth from the first-passthree-dimensional digital model.
 24. The apparatus of claim 20, whereinthe memory further comprises operational instructions that cause theprocessing module to, when the type of abnormality is a transposedtooth, extract the at least one tooth.
 25. The apparatus of claim 20,wherein the memory further comprises operational instructions that causethe processing module to, when the type of abnormality is an abnormallylarge tooth, reduce the size of the at least one tooth in the first-passthree-dimensional digital model based on a corresponding tooth on anopposite side of an arch and a normalized model tooth.
 26. The apparatusof claim 18, wherein the memory further comprises operationalinstructions that cause the processing module to: when the additionaltreatment is required, determine additional treatment options; andsimulate, in a sequential manner, each of the additional treatmentoptions.
 27. The apparatus of claim 26, wherein the memory furthercomprises operational instructions that cause the processing module to:when each of the additional treatment options fails to provide anacceptable option, utilize a compromised three-dimensional digitalmodel.
 28. The apparatus of claim 18, wherein the memory furthercomprises operational instructions that cause the processing module to:when the at least one aspect of the interim three-dimensional digitalmodel requires changing, change the at least one aspect of the interimthree-dimensional digital model.